Actaeon was transformed into a stag because he happened to see greek goddess Artemis naked
One day, while Actaeon was on his way to hunt, he stumbled upon the divine virgin Artemis, bathing naked in the woods of Orchomenos, surrounded by her Nymphs. Amazed by her beautiful body and divine grace, he couldn't help staring. When Artemis became aware of this intrusion, she got furious and punished Actaeon by transforming him into a stag.
Actaeon became fearful and fled away, but his own hunting dogs, 50 in number, jumped on him and tore him to pieces and devoured him, thinking that he was a real stag.